Process of reducing calcium oxid.



W W @J 6 1w MJZAM m M WW fi A 6 J% g m m J I ATTORNEYS.

' agent THOMAS L. \VILLSON, OF NEW YORK,

. ASSIGNMENTS, TO UNION CARBIDE OF VIRGINIA.

PROCESS OF anon Specification of Letters Patent.

N. Y., ASSIONOR, BY MESNE COMPANY, A CORPORATION CENG CALCIUM OXlD.

Patented May 8, 1906.

Application filed/January 28, 1896. Serial No. 577,117.

. T0 all/107mm if may.) concern:

Be it known that I, THOMAS L. WILLsoX, a

.citizen of the United States, formerly of Brooklyn, Kings county, New York, but now residing in the city, county, and State of New York, have invented certain new and useful Improvements in the Process s of Reducing Calcium Oxid, of which the following is a specification.

My present invention aims to overcome the difficulties inherent in the practice of electric smelting of refractory metallic compounds by incandescence.

My invention is characterized by the utilization of the principle of heating the ores or metallic compounds by the employment of the electric arc in the presence of a reducing It is well known that a much higher temperature is secured in the electric arc than in the heating of a poor conductor to incandescence by the passage of an electric current.

According to my invention I provide two electrodes of carbona lower one which may be hollowed or cup-shaped, as a crucible, and an upper one, preferably in theform of a pen- For' the lower electrode I employ, by preference, a carbon crucible placed on a conducting bed or plate of carbon, to which is joined one of the terminal wires of the electric circuit, the other wire being connected to the carbon pencil forming the other electrode.

I Preferably the positive terminal is connected to, the carbon plate and thence to the cupshaped electrode, making the latter the anode, and the negative terminal is connected to the carbon pencil, constituting the latter the cathode; but this is not essential.

This invention relates to the reduction of calcium oxid by the intense heat ofthe elec- ,tric arc: andthe, reducing action of carbon.

The reduced metal may alloy or combine with some other metal or element, if present, and

may combinewith an excess of carbon to.

form a carbid.

The materialsupon which I especially propose to work, as contemplated in this appli- Ido cation, are calcium oxid and coke.

' not, however, limit myself to the use of crushed coke, as other forms ofcomminuted carbon may be employedas, for instance,

lamp-black or the ground-up waste fragments of retort-carbon.

the heat of the are being retained and concentrated upon the work to be done, a reduction of the metallic oXid by the commingled carbon occurs, due to the high heat of the when the carbon is in excess, the highly-heated metal unites directly with the said carbon to form carbid.

The utilization of crushed coke is of special advantage as compared with hydrocarbons, in that there is less loss of heat in the treatment of such commingled coke than with a liquid or other hydrocarbon which has to be the metallic oxid is effected.

The practical application of my invention may be understood from the accompanying drawing, which is a vertical transverse section ofa suitable furnace.

of brickwork, constructed with an opening or .recess a of suitable size and shape, within which is set a crucible'B. A carbon-plate C is built into the bench A and forms the bottom or floor of the opening a,.so that the cru cible rests on this plate. The brickwork immediately surrounding the opening a should be constructed of refractory material. I D designates the dynamo which of course maybe of any suitable type adapted to generate a current of the requisite volume under suitable electromotive force and the respeccarbon plate C and 'with a carbon pencil or bon-plate is made, preferably, through the medium ofabar of metal I), as shown in dotted lines, to which the positive terminal of the wire w is fastened. The connection of the carbon pencil E may be made by a clamp c, fastened on at its upper portion and formed with a binding-post into which the end of the other wire w is fastened. f

The crucible B having been placed in the opening a, it is-covered by placing over it a cover F, which may rest either this cover in order to prevent access of air to the crucible. The cover F may be two firebricks held between plates e; A cylindrical Let A designate a suitable hearthor bench electrode E. The connection with the can i In practical operation, as will be explained,

electric arc, and in some cases, and especially converted to carbon before the reduction of fire-brick or other highly tive terminals of which are connected with the on the top of the crucible or on the top of the brickwork A. A luting of fire-clay (1 should be placed under hole g is formed vertically through the middle of the cover F and also a vent-opening h, which is preferably distinct from the hole 9. The hole 9 is made of such size as to admit the passage of the carbon pencil E through it with just sufficient friction to hold the carbon pencil at any height at which it may be placed.

The furnace may be operated for the reduction of calcium oxid in the following manner: I place in the crucible a suitable mixture, in a finely-divided condition, of calcium oxid and coke, the said coke being sufficient to reduce the calcium oxid. The vessel having been charged, the cover is then placed over the crucible and the carbon pencil E the layer of material until its tip touches the lower electrode, or the carbon pencil may be first placed in position and the material to be reduced subsequently placed around it. The circuit connections being completed,an electric current is passed through theelectrodes B and E. In a crucible containing about four or five pounds of material I have used two hundred amperes under an electromotive force of fifty volts. Of course if more material is used more amperes are to be employed. The carbon pencil E is then lifted slightly to strike the arc and higher until the maximum arc is formed. This adjustment may be either by hand or the furnace may be rovided with automatic means for regulating. the length of the arc by mechanism similar to the regulator of an arc-lamp. The fused product runs to the bottom, and the carbon pencil E is gradually lifted as the product accumulates. The pencil E should e fed up or down, as occasion requires, in order to maintain the desired arc. gases escape through the vent-hole.

In the practice of my invention I aim to prevent as far as possible the wasting away of the carbon electrodes, since carbon in this form is an expensive fuel. In fact, it is the aim of my invention to avoid as far as possible all heating by combustion, the furnace being operated as nearly as possible by electric heat alone. some oxidizable material is necessary in order to combine with the oxygen set free by the reduction of the ore I prefer to introduce into the crucible some cheaper form of car- -bon thanthat of which the electrodes are made. I have found the use of carbon in the form of lamp-black or crushed coke or the ground-up waste fragments of retort-carbon advantageous. By thus supplying carbon in this form the wasting away of the carbon pencil or cathode is reduced to almost nothis obvious that as the material is reduced additional material may be fed into the crucible, and it is also apparent that my process is advantageous, in that the material sur- The freed To this end and because.

rounding the arc protects the arcand saves its heat and concentrates it upon the work to be done.

I am aware that United States Patent N 0. 324,658, granted August 18, 1885, to E. H. and A. H. Cowles, describes and claims a process of producing alloys, bronzes, and metallic compounds, specifically aluminiumbronze, silicon-bronze, or boron bronze', in which an ore is mixed with broken carbon and with an ore of an alloying metal or pieces of such metal and smelted. The patent states thatthe process is preferably carried out in a Cowles incandescent or resistance furnace, but that other electric furnaces may be employedfor example, the Siemens thrust through it and pressed down through electric-arc furnace. The process described for the purpose of illustration is that of producing aluminium-bronze. An ore of aluminium is mixed with broken carbon and with an ore of copper or pieces of copper and smelted in an incandescent furnace, which is illustrated in the drawings. The aluminium is reduced and alloys with the reduced or melted copper. The patentees state that the same process may be practiced in the Siemens arc-furnace and that they either mix the ores or metals to be reduced to ether or alloyed or use an electrode of an al oying metal which is melted and alloys with the reduced metal.

I am also aware that an article by Dr. T. Sterry Hunt, published in The Transactions of the American Institute of Mining Engineers, Vol. 14, pages 492-5, states that E. H. and A. H. Cowles have employed the heat generated by the passage of an electric current through a resisting medium as a means of reducing in the presenceof carbon the oxids not only of the alkaline metals, but of calcium, &c.

I am also aware that the Journal of the Society of Telegm h Engineers, Vol. 9, page 278, illustrates an describes the Siemens arcfurnace, including an automatic electromagnetic regulator for maintaining an arc of uniform resistance, and states that this regulator adjusts the arc to compensate for the sudden sinking or change in electrical resistance of the material undergoing fusion. The description also states that it is necessary to provide a. non destructible positive pole, such as platinum or iridium, when operating upon non-conductive earth or upon gases. The drawing of the furnace shows a suspended pole or electrode wholly out of contact with the-contents of the crucible, the are being sprung from the lower end of the electrode to the steel-in the crucible.

What I claim as my invention, and desire to secure by Letters Patent, is

1. The herein-described process of reduc ing calcium oxid by the action of carbon commin led therewith and the heat generated by an eIectric arc, which consists in establishing an electric are between suitable poles, embedding the are within a charge of calcium oxid and carbon, reducing portions of the charge,- accumulating the product into a mass, thereafter employing said mass as one pole of the arc and maintainin the are as the mass accumulates by gradual y moving one of the poles of the arc, keeping unreduced portions of the charge around the arc, thereby retaining the heat of the arc and concentrating it upon the work to be done, and substantially excluding the air from the zone of reduction and permitting the escape of the gases produced by the reduction.

2. The herein-de'scribed process of reducing calcium oxid by the action of carbon c0mmin led therewith and the heat generated by an electric are, which consists in establishing an electric are between suitable poles, one of said poles being the end of a carbonelectrode, embedding the arc.in a charge of calcium oxid and carbon, reducing portions of the charge, accumulating the; product into a mass, thereafter empoying said mass as one electrode and maintaining the are between said mass and said carbon electrode by gradually moving one of said electrodes, keeping unreduced portions ofthe charge in contact with the carbon electrode and aro nd the arc, thereby retaining the heat of-the arc and concentrating it upon'thework to be done, and substantially excluding the air from the zone of reduction and permitting the escape 1 of the ases produced by the reduction.

3. T e herein-described process of reducing calciumoxid bythe action of carbon commingled therewith and the heat generated byan electric-arc, which consists in establishing an electric are between suitable poles, em-

bedding the arc within a charge of calciumv oxid and carbon, reducing portions of the charge, accumulating the product into a mass, thereafter employing said mass asone pole of the arc and maintainin the are as the mass accumulates by gradually movin one of the poles of the are, keeping unre need portions of the charge around the arc;and

around the hot portions of said mass, thereby retaining the heat of the are and concentrating it upon the work to be done, and substantially excluding the air from the zone of reduction and permitting the escape of the gases produced by the reduction.

4. The herein-described process of reducing calcium oxid by the action of carbon commm an e ectric are. which consists in establishing an electric are between suitable poles, one of said poles being the end-of acarbon electrode, embedding the are in a charge of calcium oxid and carbon, reducing portions of the charge, accumulatin the product into a mass, thereafter emp oyingsaid mass as one electrode and maintaining the are between said mass and said carbon electrode by gradled therewith and the heat generated by ually moving'oneof said electrodes, keeping unreduced portions of the charge in contact with the carbon electrode and around the arc and the hot portions of said 'mass, thereby retaining the heat of the arc and concentrating it upon the work to be done, and substantially excluding the air from the zone of reduction and ermitting the escape of the gases produced y the reduction.

5. The herein-described process of reducin calcium oxid by the action of carbon commin led therewith and the heat generated by an e cctric arc, which consists in establishing an electric are between suitable poles, one of said oles being the end of a dependin carbon dlectrode, embedding the'arc in a charge of calcium oxid and carbon, reducing portions of the charge, accumulating the product intoa mass, thereafter employing said mass as one electrode and maintaining the are between said mass and said depending carbon electrode by gradually moving one of said electrodes, keeping unreduced portions of the charge in contact with the depending carbon electrode and around the arc, thereby retaining the heat of the arc and concentrating it upon the work to be done, and substantially excluding the air from the zone of reduction and permitting the escape of the gases produced by the reduction.

6. The herein-described process of reducing calcium oxid by the action of carbon commln led therewith and the heat generatedby an e ectric arc, which consists in establishing an electric are between suitable poles, one of said poles being the end of a dependin carbon electrode, embedding the arc in a c large of calcium oxid and carbon, reducing portions of the charge, accumulatin the product into a .mass, thereafter emp oying said mass as one electrode and maintaining the are between said mass and said depending carbon electrode by gradually moving one of said electrodes, keeping unreduced portions of the charge in contact with the depending carbon electrode and around the arc and the hot portions of said mass, thereby retaining the heat of the arc and concentrating it upon the Work to be done, and substantia y excluding the air from the zone of reduction and per: mitting the escape of the gases produced by the reduction.

-7 The herein-described process of continuously reducing calcium oxid by the action of carbon comnnngled therewith and the heat enerated by an'electric are, which consists 1n establishing an electric are between suitable poles, embedding the arcv within a charge of calcium oxid and carbon, reducing portions of the charge, accumulating the product into a maSs thereafter employing said mass asone pole of the arc'andniaintaining the are as the massaccuniulates by radually moving one of the poles of the arc, ceding in additional material as required and keeping unreduced portions of the charge around the arc, thereby retaining the heat of the arc and concentrating it upon the work to.be done, and substantially exclud- 5 ing the air from the zone of reduction and Ipermitting the escape of the gases produced v y the reduction.

8. The herein-described process of continuously reducing calcium oxid by the action of carbon commmgled therewith and the heat generated by an electric arc, which consists in establishing an electric arc between suitable poles, one of said poles being the end of a carbon electrode, embedding the arc in a charge of calciumoxid and carbon, reducing portions of the charge, accumulating the product into a mass, thereafter employing said mass as oneelectrode and maintaining the arcbetween said mass and said carbon electrode by gradually moving one of said electrodes, feeding in additional material as required and keeping unreduced portions of the charge in contact with the carbon electrode and around the arc, thereby protecting said electrode and retaining the heat of the arc and concentrating it upon the work to be done, and substantially excluding the air from the zone of reduction and permitting. the escape of the gases produced by the reduction. v

i 9. The herein-described process of continuously reducing calcium oxid by the action of carbon commingled therewith and the heat I generated by an electric arc, which consists in establishing an electric are between suitable poles, one of said poles being the end of a depending carbon electrode, embedding the arc in a charge of calcium oxid and carbon, reducing portions of the charge, accumulating the product into a mass thereafter employing said mass as one electrode and maintaining the arc between said mass and said depending carbon electrode by gradually moving one of said electrodes, feeding in additional'material as required and keeping unreduced ortions of the char e in contact with the epen ding' carbon e ectrode and around the arc and the hot portions of said mass, thereby protecting said electrode and mass, retaining the heat of the arc and concentrating. it upon the work to be done, and substantially excluding the air from the zone of reduction and permitting the escape of the gases produced by the reduction.

10. The herein-described process of producing calcium carbid, which consists in establishing an electric are between suitable poles, einbeddin the are within a charge of calcium oxid and carbon, using suitable proportions for the production of calcium car bid, reducing portions of the charge, accum ulating the carbid into a mass, thereafter employing said mass as one pole of the arc and maintaining the arc as the mass accumu lates by gradually moving one of the poles of the arc, keeping unreduced portions of the charge around the are, thereby retaining the heat of the arc and concentrating it upon the work to be done, and substantially excluding the air from the zone of reduction and permitting the escape of the gases produced by the reduction.

11. The herein-described process of producing calcium carbid, which consists in establishing an electric are between suitable poles, one of said poles being the end of a carbon electrode, embedding the arc in a charge of calcium oxid and carbon, using suitable proportions for the production of calcium carbid, reducing portions of the charge, accumulating the carbid into a mass, thereafter employing said mass as one electrode and maintaining the arc between said mass and said carbon electrode by gradually moving one of said electrodes, keeping unreduced portions of the charge in contact with the carbon electrode and around the are, thereby retaining the heat of the arc and concentrating it upon the Work to be done, and substantially excluding the air from the zone of reduction and permitting the escape of the gases produced by the reduction.

12. The herein-described process of producing calcium carbid, which consists in es tablishing an electric are between suitable poles, embedding the arc within a charge of calcium oxid and carbon, usin suitable proportions for the production of calcium carbid, reducing portions of the charge, accumulating the carbid into a mass, thereafter employing said massas one pole of the arc and maintaining the are as the mass accumulates by gradually moving one of the poles of the arc, kee ing unreduced portions of the charge aroun the arc and around the hot ortions of said mass, thereby retaining the libat of the arc and concentrating it upon the work to be done, and substantially excluding the air from the zone of reduction and permitting the escape of the gases produced by the reduction.

13. The herein-described process of producing calcium carbid, which consists in establishing an electric arc between suitable poles, one of said poles bein the end of a carbon electrode, embedding the arc in a charge of calcium oxid and carbon, using suitable proportions for the production of calcium carbid, reducing portions of the charge, accumulating the carbid into a mass, thereafter employing said mass as one electrode and maintaining the are between said mass and said carbon electrode by gradually moving one of said electrodes, keeping unreduced portions of the charge in contact with the carbon electrode and around the arc and the hot portions of said mass, thereby retaining the heat of the arc and concentrating it upon the work to be done, and substantially excluding the air from the zone of reduction and permitting mass, thereby retaining the and concentrating it upon the Work to bev eeaoai the escape of the gases produced by the reduction.

14. The herein-described process of producing calcium carbid, which consists in-establishing an electric arc between suitable poles, one of said. poles being the end of a depending carbon electrode, embedding the arc in a charge of calcium oxid and carbon, using suitable proportions for the production of calcium carbid, reducing portions of the charge, accumulating the carbid into a mass, thereafter employing said mass as one electrode and maintaining the are between said mass and said depending carbon electrode by gradually moving one of said electrodes, keeping unreduced ortions of the char e in contact with the epending carbon efectrode and around the arc, thereby retaining the heat of the arc and concentrating it upon the work to be done, and substantially excluding the air from the zone of reduction and permitting the escape of the gases produced by the reduction.

15. The herein-described processtof producing calcium carbid, which consists in establishing an electric arc between suitable poles, one of said poles being the end of a depending carbon electrode, embedding the arc in a charge of calcium oxid and carbon, using suitable pro ortions for the production of calcium carliid, reducing portions of the charge, accumulating the carbid into a mass, thereafter employing said mass as one electrode and maintaining the are between said 'mass and said depending carbon electrode by gradually moving one of said electrodes, keeping unreduced portions of the charge'in con tact with the depending carbon electrode and around the arc and the hot done, and substantially excluding the air from the zone of reduction and ermitting the escape of the gases produced by the reduction. i. g

16. The herein-described process of producing calcium carbid, which consistsin establishing an elec'tricar'c between suitable poles, embeddin the arc within a charge of calcium oxid an carbon, using suitable roportions for the production of'calciumcar id, reducing portions of the charge, accumulating the carbid into a mass, thereafter employing said mass as one pole of the arc and maintaining the are as the mass accumul tes by gradually moving one of the oles of he arc, feeding in additional materia as re uired and keeping unreduced portions of the c arge plortions of said eat of the arc reduction ,and

around the arc, thereby retaining the heat of the arc and concentrating it upon the work to be done, and substantially excluding the air from'the zone of reduction and permitting the escape of the gases produced by the reduction. g 17. The herein-described process ofproducing calcium carbid, which consists in establlshing an electric are between s'uitable poles, one of said poles bein the end of a car- 'bon electrode, embedding t e are in a charge of calcium oxid and carbon, using suitable proportions for the production of calcium car bid, reducing ortions of the charge, accumulating the car id into a mass, thereafter employing said mass as one electrode and maintaining the arc between said mass and said carbon electrode by gradually moving one of 0 said electrodes, feeding in additional material as required and keeping unreduced portions of the charge in contact with the carbon electrodeand around the arc, thereby protecting said electrode and retaining the heat of the arc and concentrating it upon the work to be done, and substantially excluding the, air from the zone of reduction and germitting the escape of the gases produced y the reduction.

18. The herein-described process of producing calcium carbid, which consists in establishing an electric arc poles, one of said poles being the end of a deending carbon electrode, embedding the arc in a charge of calcium oxid and carbon, using suitable roportions for the production of calcium car id, redu'cing portions of the charge, accumulating the carbid into'a mass, thereafter employing said mass as one electrode and m lntaining the arc; between said mass and said depending carbon electrode by grad ing unreduced portions of the charge in contact with the depending carbon'electrode and around the arc and the hot portions of said "mass,

thereby protecting said electrode and mass, retaining the heat of the arc and concentrating it upon the work to be done,-and substantially excluding the air from the zone of permitting the escape of the gases produced by the reduction.

,I-n witnesswhereof I have hereunto s1 ned my name in the presence of two subscri ing witnesses.

' THOMAS L. WILLSON. Witnesses:

, ARTHUR C. FRASER, GEORGE H. FRAsER.

between suitable 

